1. Field
Embodiments relate to a substrate including a thin film transistor, a method of manufacturing the substrate, and an organic light emitting display apparatus including the substrate.
2. Description
Flat display devices may include emissive type and a non-emissive type display devices. Emissive type display devices may include, for example, flat cathode ray tubes, plasma display panels (PDPs), and electroluminescent display devices. Non-emissive type display devices may include liquid crystal displays (LCDs). Electroluminescent display devices may have a wide viewing angle, excellent contrast, and rapid response speed and, thus, have recently been highlighted as the next generation display devices. Such electroluminescent display devices may include inorganic electroluminescent devices or organic electroluminescent devices, referring to the materials for forming an emission layer.
Organic electroluminescent devices may be used in self-luminous displays that emit light by electrical excitation of fluorescent organic compounds. As the electroluminescent devices may be driven using a low voltage, may be easily made thin, and have a wide viewing angle and rapid response speed, they have received considerable attention.
An organic electroluminescent device may include an emission layer formed of an organic material and interposed between an anode and a cathode. When an anode voltage and a cathode voltage are respectively applied to the anode and the cathode, holes injected from the anode move to the emission layer through a hole transport layer and electrons move from the cathode to the emission layer through an electron transport layer, so that the holes and the electrons recombine in the emission layer and form excitons.
The excitons transition from an excited state to a ground state, thereby making the fluorescent molecules of the emission layer emit light and form an image. A full-color type organic electroluminescent device may include pixels that emit red R, green G, and blue B color to thus realize a full color image.
In such an organic electroluminescent device, a pixel defining layer may be formed on both ends of the anode. A predetermined opening may be formed in the pixel defining layer. Then, the emission layer and the cathode may be sequentially formed on the anode exposed to the outside through the opening.